- Previous Article
- Next Article
- Table of Contents
Langmuir, Vol.17, No.8, 2283-2286, 2001
Formation of multilayer composite particles comprised of silica/vesicle/silica particles by heterocoagulation
The multilayer composite particles comprised of silica/PC (phosphatidylcholine) vesicle/silica particles have been prepared by using the heterocoagulation technique. The formation process is as follows: at first, large silica particles (2r = 1.5 mum) and PC vesicles (2r = 0.2 mum) were mixed at a definite particle number ratio in 10(-4) M LaCl3 aqueous solution. The PC vesicle/silica composites were spontaneously formed by mutual electrostatic attraction. After removal of the excess PC vesicles from the system, the small silica particle (2r = 0.5 mum) suspension was added into the PC vesicle/silica composite dispersions to form the multilayer composite particles composed of small silica, PC vesicle, and core silica particles. The formation of multilayer composite particles was confirmed by the electrophoresis, dynamic light scattering (DLS), and adsorption measurements of PC molecules. Finally, the existence of multilayers was confirmed directly using a special optical microscope.